Apparatus and method for curving tubing

ABSTRACT

A stationary forming die around which a wiper die is moved to curve tubing interposed therebetween, and a feed-through chuck through which the tubing is advanced in increments into the space between the said dies; the chuck being rotated to permit successive curves to be formed in the tubing in relatively offset planes.

I United States Patent [191 [111 3,863,483

Wright et al. 1 Feb. 4, 1975 APPARATUS AND METHOD FOR CURVING [56] References Cited TUBING UNITED STATES PATENTS [75] Inventors: Peter C. Wright, Etobicoke; Donald 3,236,082 2/l966 Beck et at 72/149 L. Kirsch, Toronto, Ontario, both of 3,299.68! 1/1967 Hautau 72/l56 X Canada l73| Assigncc: Gidon Industries, Inc., Rcxdale, Primary Mammer Mllmn Mehr Ontario, Canada I [57] ABSTRACT [22] Filed: May A stationary forming die around which a wiper die is [21] Appl. No.: 359,994 moved to curve tubing interposed therebetween. and a feed-through chuck through which the tubing is advanced in increments into the space between the said if gj gz dies; the chuck being rotated to permit successive g I57 149 curves to be formed in the tubing in relatively offset ib/56 plamw 19 Claims, 15 Drawing Figures PATENTEB FEB 41ers SHEEI 10F 6 PATENTED 3,863,483

SHEET 30F 6 PATENTED 4W5 3.863 ,483

SHEET 5 or 6 FIG. 11.

FIG. 12.

APPARATUS AND METHOD FOR CURVING TUBING This invention is directed broadly to a method and means for forming intricate convolutions in metal tubing. in particular, the invention relates to a method of, and apparatus for forming successive calculated curves in the tubing with very little, if any, material distortion of its caliber. Moreover, the invention is further concerned with the formation of such curves in various planes.

The method and apparatus for curving tubing as visualized by the invention is directed towards forming a plurality of successively curves in tubing pursuant to a preselected pattern; said curves being capable of being formed with various degrees of curvature and in relatively offset planes as set forth by said pattern.

A pattern as contemplated herein may provide specific instructions to be carried out during the operation of the apparatus aforesaid. That is to say, the apparatus according to the present invention includes various gauging instrumentalities and controls which are manipulable by an operator in accordance with the pattern instructions in order to produce a length of metal tubing with curves which are spaced apart and offset relative to each other according to a pre-selected shape.

The method and apparatus for curving tubing as visualized herein is of avail when tubing must be shaped to fit within an irregular location of more or less tortuous character. One primary use for such curved tubing is as an automobile exhaust pipe; it being appreciated that there are numerous obstructions in the path pursued by an exhaust pipe between the engine and muffler and/or muffler and discharge at the rear of the vehicle; these obstructions being created by chassis frame members, struts, axles, and so forth. Accordingly, the exhaust pipes must be curved to avoid these obstructions and to fit between them. It will be appreciated that virtually each automobile model may require its own individually shaped exhaust pipe and having regard to the wide variety of automobiles in current use it will be understood that many different types of exhaust pipes have heretofore been necessitated to conform to these divers constructions.

Because of the unfavorable environment to which these several types of exhaust pipes are invariably exposed, they are, of course, susceptible to corrosion and, hence, must very often be replaced with more or less frequency, particularly since they are subjected not only to corrosive exhaust gases but also to adverse weather conditions in which they tend to deteriorate rather rapidly. As a result, it has heretofore been a common necessity for distributors of exhaust pipes to carry a large and costly inventory hereof in order to service the several models of automobiles.

The invention, on the other hand, seeks to obviate this requirement and in furtherance of this cost saving advantage, the invention makes it possible to meet all ordinary exigencies by maintaining only straight tubings differing from each other chiefly in size. Thereafter, when and if an exhaust pipe is required for replacement, a selected size of straight tubing is then curved according to the invention pursuant to a designated pattern programmed for the particular model of automobile concerned; it being understood, of course, that each model of automobile will have a curving pattern to fit its own intricate design.

in furtherance of its objectives and for reasons which will appear the invention visualizes the use of tubing formed of malleable metal or its equivalent, which is corrugated.

An important object of this invention is to provide apparatus and method for forming successive curves in tubing; said apparatus being operable to form variously spaced curves in various degrees of curvature and in relatively offset planes pursuant to a curving pattern, particularly in malleable, corrugated tubing.

The invention further visualizes a method of shaping tubing permitting the formation of intricately shaped tubes conforming to pre-selected patterns.

The invention still further visualizes the provision of apparatus as aforesaid equipped with means for spacing said curves on the tubing, for limiting its respective degrees of curvature thereof and for offsetting said curves relative to each other.

To achieve the foregoing and other obvious objects both stated and unstated hereinafter. the present invention broadly provides a method comprising the steps of: supporting the tubing in an axially stationary rotatable chuck, with one end of the tubing projecting through said chuck; training said projecting end between a forming die and a wiper die; withdrawing said tubing through said chuck by its projecting end in linear increments, and advancing it between said forming die and wiper die; curving preselected portions of said tubing around said forming die to form curves of predeter mined angularity therein, and rotating said chuck after the formation of at least one of the curves to procure a succeeding curve in a plane which is offset relative to the plane of its predecessor.

in a correspondingly broad aspect, the apparatus comprises a tube curving head including, a forming die about which said tubing is curvable and a wiper die spaced from said forming die to permit the tubing to be interposed between it and the forming die, the wiper die being movable to curve said interposed tubing around said forming die whereby to form curves therein; a rotatable chuck for yieldingly supporting said tubing in interposed relation between said forming die and wiper die as aforesaid, said chuck being of the feed-through type permitting the tubing to be advanced through the chuck towards the forming die and means for engaging said tubing supported in said chuck and for advancing metered portions thereof to said tube curving head for curving as aforesaid; the tubing being co-rotatable with the chuck to permit formation of successive curves in relatively offset planes.

Other objects of the invention more or less broad than the foregoing will become apparent from the hereinafter following description of the elements, parts and principles of the invention given herein solely by way of example and with reference to the accompanying drawings wherein like reference numerals refer to like parts and wherein:

FIG. 1 is a perspective view of the tube curving apparatus according to the preferred embodiment of the invention; parts being removed from the shaft to reveal the chuck;

FIG. 2 is a front elevational view of the tube curving apparatus taken along lines ll-ll in FIG. 1; the removed parts of FIG. 1 being included in this view;

FIG. 3 is a top plan view of that portion of the tube curving apparatus shown in FIG. 2 taken along lines III- III therein;

FIG. 4 is a side elevational view of a portion of the forming die and its lock also shown in part in FIG. 1;

FIG. 5 is a side elevational view of the fixed and rotatable stop members shown in FIGS. 1 to 3; parts being removed from the fixed stop member to reveal the manner in which it intercepts the rotatable stop member;

FIG. 6 is a perspective view of the wiper die being held in its normal pre-curving position as a result of its associated arm engaging a magnet;

FIG. 7 is a side elevational view of a portion of the chuck supporting a small size tubing;

FIG. 8 is a side elevational view of a portion of the chuck supporting a large size tubing;

FIG. 9 is a perspective view of the advancing means shown in isolation;

FIG. 10 is a view of a portion of the advancing means taken along lines X-X in FIG. 9 and showing how the advancing element is tiltable on an inclinable axis;

FIGS. 11, I2 and 14 are schematic views in side elevation of the tubing at various stages in its advancement through the curving apparatus;

FIG. I3 is a schematic view in side elevation of the tubing formed with a first curve by being wrapped around the forming die by the wiper die, and

FIG. 15 is a schematic view in side elevation of the tubing having been initially rotated from its position of FIG. 14 and subsequently formed with a second curve having its plane resultantly offset relative to the plane of the first curve.

According to a preferred embodiment of the invention apparatus for forming successive curves in tubing and in relatively offset planes is illustrated generally in FIG. I. As shown therein, the apparatus comprises a tube curving head A including a forming die 2 about which malleable tubing is curvable and a wiper die 4 spaced from said forming die 2 to permit tubing T to be interposed between it and forming die 2 as shown in FIGS. 2, II and 13; said wiper die 4 being movable as will appear from FIG. 13, to curve said interposed tubing T around said forming die 2 whereby to form curves therein as will be described hereinafter in greater detail. In addition thereto, the curving apparatus also embodies a rotatable chuck C for yieldingly supporting said tubing T in interposed relation between said forming die 2 and wiper die 4 as aforesaid; said chuck C being of the feed-through type (FIG. '7) permitting the tubing T to be advanced through it towards said curving head A. In order to effect such movement the invention visualizes means E as best shown in FIG. 9 for engaging said tubing T supported in said chuck C and advancing metered portions thereof to said tube curving head A for curving as aforesaid. Since said tubing T is supported in said rotatable chuck C it will be understood, of course, that the tubing is also co-rotatable therewith thereby permitting formation of successive bends in relatively off-set planes as will become apparent hereinafter.

With some particular regard now to said tube curving head A and especially to forming die 2, the solid and dotted line positions of FIG. 2 illustrate it as being adjustable to permit tubing of various sizes to be installed between it and said wiper die 4. Specifically, said forming die 2 includes a spool 6 mounted in this preferred embodiment on a rotatable shaft 8 which in turn is journalled in spaced standards 10 and 12; said spool 6 having collars l4 and I6 constituting jaws which are screwthreadedly engaged thereon for movement towards and away from each other as shown by said dotted and solid lines, respectively, to define and bound a groove 18 on the rim of said spool 6 in which the tubing is seatable; said collars l4 and 16 being chamfered as at 20 and 22, respectively, to impart a V-shaping to said groove 18. Further thereto, said forming die 2 also embraces a coupling 24 for coupling said collars l4 and 16 for conjoint rotation about said spool 6; the screw threading being right and left handed procuring variation in the spacing between said collars 14 and I6 when they are rotated as aforesaid. In this embodiment said coupling 24 includes a dowel 26 fixed by one end to said collar 16 as at 28 (FIG. 2) with its other end projecting through an opening 30 provided in the other collar 14 as best shown in FIG. 1. Thus, it will be understood that because of said coupling 24 and the right and left hand threading aforesaid, said collars or jaws l4 and I6 will move conjointly on said spool 6 either in a spreading or contracting relationship as shown by said solid and dotted lines, respectively, in FIG. 2 to vary the width of said groove I8 in conformity with the tubing sizes; the variance in the width of said groove 18 constituting the forming die adjustment aforesaid.

Since the main purpose ofthe forming die adjustment is to conform said forming die 2 to accommodate various tubing sizes as aforesaid, the invention visualizes equipping said dowel 26 with a scale 32 as shown in FIG. 3 for indicating variations in the spacing of said collars 14 and 16 when they are rotated as aforesaid. In a working model of the invention, said collars l4 and 16, spool 6 and the thread pitch are dimensioned and proportioned to impart an adjustment of A inch to said forming die 2 for each complete rotation of said collars l4 and 16 about said spool 6. Hence, it will be recognized from FIG. 3 that said scale 32 is graduated in increments of '1 inch, approximately, for measuring such adjustment permitting use of tubing varying in diameter from l /z to 2% inches.

Once said forming die 2 is adjusted, it is desirable that the adjustment be fixed temporarily for obvious reasons. Accordingly, a lock 34 as shown in FIGS. 1 and 4 is provided for releasably locking said collars l4 and 16 to said spool 6 to prevent them from rotating thereabout. More particularly, said lock 34 includes a key 3 as best shown in FIG. 4 pivotally mounted on said collar 14 as at 38 and a keyway 40 formed in said spool 6; said key 36 being swingable into and out of locking engagement with said keyway 40 as shown by solid and dotted lines respectively, to lock and unlock said col lars l4 and 16 relative to said spool 6. Thus, it will be appreciated that when said collars l4 and 16 are unlocked they may be rotated as desired to effect the ad justment of said forming die 2 whereupon they are then locked to spool 6 by said key 36 to maintain the adjustment temporarily.

With more individual attention now to said wiper die 4, FIGS. 2 and 13 depict it to be mounted for movement in a fixed orbit about said forming die 2; means 42 shown in FIG. 2 being provided for procuring such movement. In particular, said wiper die 4 includes a sheave 44 rotatably engaging said tubing T when said wiper die 4 is moved to wrap the tubing about the forming die 2 to curve it as aforesaid; said sheave 44 being mounted as best shown in FIG. 2 to one end of an arm 46 as at 48 with arm 46 in turn being fixed by its opposite end to said rotatable shaft 8 as at 50 to be comovable therewith. Resultantly, therefore, said wiper die 4 will move in a fixed orbit about said forming die 2 when said shaft 8 is rotated as shown schematically in FIG. 13. To procure orbital movement of said wiper die 4 said moving means 42 is constituted in this embodiment by a lever 52 attached to one end of said shaft 8 as shown in FIG. 2, for example; said lever 2 being manipulable by hand for manually implementing rotation of said shaft 8 and, of course, concomitant orbital movement of said wiper die 4 about said forming die 2 as aforesaid.

Having regard to the foregoing, the invention further visualizes providing means 54 as shown in FIGS. 1 to 3 for limiting the movement of said wiper die 4 about said forming die 2 to procure curves in said tubing of specific proportions. More explicitly, said limiting means 54 embodies cooperating fixed and rotatable stop members 56 and 58, respectively; said rotatable stop member 58 being secured to said shaft 8 as at 60 for movement therewith through a finite locus, as illustrated by its solid and dotted line positions of FIG. 5, in tandem with said wiper die 4. Said fixed stop member 56, on the other hand, is positionable at various points in the locus aforesaid as shown by its solid and dotted line positions of FIG. 3 to intercept said rotatable stop member 58 when it is in its dotted line position in FIG. 2 for example, to limit the movement of said wiper die 4. That is to say, said fixed stop member 56 includes a hollow handle 62 telescoped over said shaft 8, enabling it to move both radially and longitudinally thereof into and out of fixed engagement with the rim 64 of a disc 66 axially aligned with said shaft 8 and attached to said standard as at 68 (FIG. 1); said stop member 56 and rim 64 having mating tongue and groove connectors 70 and 72, respectively. In order to prevent inadvertent disengagement of said stop member 56 from said rim 64 a spring 74 is also telescoped over said shaft 8 and positioned between said handle 62 and a cap 76 fixed to shaft 8 as shown in FIG. 2; said spring 74 serving to bias said stop member 56 into fixed engagement with said rim 64 as aforesaid. Thus, it will be appreciated that said fixed stop member 56 can be selectively positioned at various points along said rim 64 in the locus aforesaid to intercept said rotatable stop member 58. In addition thereto, said limiting means 54 further includes a register 78 illustrated in FIG. 3 for identifying the respective points at which its said fixed stop member 56 is positionable as aforesaid; said register 78 including a pointer 80 and scale 82 with said pointer 80 being on said stop member 56 and said scale 82 on said standard 10 in this embodiment.

By way of brief summary, therefore, said fixed stop member 56 is selectively positioned in said locus in accordance with curving pattern instructions whereupon said lever 52 is manipulated to move said wiper die 4 to curve the tubing T about said forming die 2 as aforesaid. Such movement continues until said rotatable stop member 58 abuts said fixed stop member 56 as illustrated in FIG. 5 signalling the end of wiper die movement and completion of the curve. Thereafter, said wiper die 4 is returned to its normal precurving position.

As a means for keeping said wiper die 4 in normal position when not being utilized, a magnet 84 as shown in FIG. 6 is attached to said standard 12 as at 86 and positioned to magnetically attract said arm 46; it being understood, of course, that this magnetic attraction is capable of being easily broken as and when said lever 52 is manipulated by the operator.

As illustrated in FIG. 1 said chuck C includes a cylindrical body portion 88 journalled in spaced plates 9090 and embraced by a complement of spaced antifriction rollers 92 mounted on said plates 90-90 as at 94; said cylindrical body portion 88 having a circumferential groove 96 engaged by a tongue 98 fixed to one said plate 90 as at 100 to prevent axial movement of said body portion 88. In addition thereto. said body portion 88 further includes an annular disc I02 fixed at one end thereof on which an adjustable gripper assembly 104, to be described. is movably mounted in an axial relationship to constitute an integral part of said chuck C.

Said gripper assembly 104 includes in this preferred embodiment an annular base plate 106 as best shown in FIG. 1 having lugs 108 fixed adjacent equally spaced and circumferentially arranged slots 110 which in turn provide accommodation for a complement of fingers 112 as shown in FIG. 7, for example. Intermediate its ends 114 and 116 said fingers 112 are pivotally mounted to said lugs 108 as at 118 and are positioned in said slots 110 so that finger ends 114 and 116 project away from said base plate 106 on opposite sides thereof. Further thereto, said gripper assembly 104 includes a cylinder 120 axially aligned with and fixed by one of its ends to said annular base plate 106; said cylinder 120 having an outer diameter substantially equal to the inner diameter of said cylindrical body portion 88.

The mounting of said gripper assembly 104 to said annular disc 102 in an axial relationship is achieved by initially telescoping the free end of said cylinder 120 through it and into said cylindrical body portion 88 until said finger ends 114 are contiguous with said disc 102 as depicted by one such finger 112 in FIG. 7. Bolts 122 are then inserted through aligned holes 124 and 126 (FIG. I) in said mounting disc [02 and base plate 106, respectively to fasten them together; springs 128 being disposed on said bolts 122 to bias said gripper assembly 104 and particularly, its associated finger ends 114 into engagement with said disc 102. It will be understood that finger ends 114 are biased against said disc 102 to project in an angular diverging relationship away from the rotary axis of said chuck C while opposite finger ends 116 are biased to project in an angular converging relationship towards a common focus on the rotary axis of said chuck C as best shown in FIG. 1. Resultantly, therefore, said chuck C includes a complement of resilient fingers 112 for gripping the tubing T in the chuck C and positioning and supporting it in the axis of rotation of the chuck C; said fingers 112 being resiliently spreadable to permit tubing of various sizes to be gripped and supported as aforesaid. Perhaps this spreading effect may be best understood by refer ring to FIGS. 7 and 8 and comparing the relative positions of one such finger 112 when it is engaged with different size tubings T supported in said chuck C. Specifically, it is seen from FIG. 7 that in the case of a small size tubing T finger end 116 assumes a somewhat pronounced converging relationship with respect to the chuck axis in order to engage tubing T. Conversely, in the case of a large size tubing T as illustrated in FIG.

8 finger end 116 spreads to assume a comparatively less pronounced converging relationship with respect to the chuck axis. Accordingly, it will be appreciated that said fingers 112 will spread proportionately to the size of tubing T supported by said chuck C. Since said tubing T is advanced through chuck C as aforesaid said finger ends 116 include rollers 130 mounted thereto at 132 which serve to engage said tubing T to facilitate such advancement.

Referring once again to said disc 102, FIG. 1 illustrates it to include a gauge 134, scaled from to 360, which is read from a pointer 136 mounted on one said plate 90 as at 138 (FIG. 7). Thus, the amount of rotation in which said chuck C must be moved pursuant to curving pattern instructions may be measured from said gauge 134 in relation to said pointer 136.

Since said chuck C is adjustable for supporting tubing T of various sizes as aforesaid, it follows that said advancing means E must also be adjustable to serve its intended purposes. To this end, HO. 9 illustrates said advancing means E to include a circular element 140 for advancing said tubing T in equal linear increments and a counter 142 for counting said increments; said element 140 being mounted for tangential engagement with said tubing T on an axis which is inclinable to accommodate tubing of various sizes. That is to say, said advancing element 140 is fixed to a rod 144 disposed transversely of the chuck axis which is inclinable as shown schematically by its dotted and solid line positions in FIG. to permit tangential driving engagement of said advancing element 140 with the tubing T, irrespective of the size of said tubing T, whereby to withdraw it through chuck C and to advance it towards the curving head A. As shown in FIG. 11 positive driving engagement between the advancing element 140 and tubing T is herein achieved by regularly corrugating said tubing T and utilizing a gear with commensurately spaced and mating teeth 146 constituting said advancing element 140.

Amongst others which are more or less obvious, one advantage accruing from the use of corrugated tubing is the positive advance imparted thereto by the advancing element 140 thereby insuring reliable measurement of said advance by said counter 142.

Another noteworthy advantage accruing from corrugating the tubing T as herein visualized for use with the present apparatus and in the present method is that much less care is required to keep it from buckling and kinking under the bending forces.

Referring once again to FIG. 9, it is seen that said rod 144 is journalled in spaced universal bearings 148 and 150 which are mounted on said standards 10 and 12, respectively in a manner to be described hereinafter. in addition to said advancing element 140, said rod 144 includes a crank 152 fixed at one end thereof for turning it and a pulley 154 fixed at its opposite end; said pulley 154 being linked to said counter 142. That is to say, said counter 142 is suitably mounted to said standard 12 as at 156 and includes a knob 158 for zeroing it as well as a pulley 160 adapting it for assemblage with a belt 162. Said belt 162 is engaged with said counter pulley I60 and rod pulley 154 to link them as aforesaid and in order to provide a tight engagement said belt 162 is trained over an idler pulley 164 which is suitably mounted to said standard 12 as at 166. Accordingly, it will be understood that rotation of said crank 152 will cause concomitant rotation of said advancing element and said rod pulley 154 to actuate said counter 142 thereby rendering a linear measurement of the distance travelled by said advancing element 140 and, hence, a like distance travelled axially by said tubing T engaged therewith.

it will be recalled that said advancing element 140 is mounted on an axis i.e., rod 144 which is inclinable to accommodate tubing of various sizes This being the case, the preferred embodiment of the invention visualizes said universal bearing as being fixed to said standard 12 as at 168 (FIG. 9) while the other universal bearing 148 is fixed to the end of a rocker arm 170 as at 172 which in turn is pivotally mounted to said standard 10 as at 174 (FIG. 1). Thus, pivotal movement of said rocker arm 170 will be accompanied by tilting or inclining movement of said rod 144 and, of course, said advancing element 140 in an understood manner.

To set said advancing element 140 for meshing engagement with a particular size of tubing, a dial 176 also shown in FIG, 1 is provided below said rocker arm 170 for propping it; said dial 176 being rotatably mounted on said standard 10 as at 178 and including in this embodiment prop surfaces 180, 182, 184, 186 and 188, each in the form of a different chord thereon which is dimensioned and proportioned to cooperate with said rocker arm 170 to thus position said advancing element 140 correspondingly to a particular size of tubing. On the face of said dial 176 is appropriate indicia 190 opposite each said prop surface signifying the size of tubing T to which it corresponds. Accordingly, said dial 176 may be rotated to selectively dispose one said prop surface below said rocker arm 170 to prop it in accordance with the size of tubing to be advanced. Once rocker arm 170 is correctly positioned, it will be understood that said advancing element 140 is then set for meshing engagement with the desired size of tubing T which is to be advanced.

Since the curves to be formed in said tubing T must be accurately placed as measured by said counter 142 a removable starting barrier 192 illustrated in FIGS. 1 and 2 is provided at which the advancing end of said tubing T is initially positioned. In that event, said counter 142 is then zeroed for subsequent measurement of the tubing advancement pursuant to curving pattern instructions. In this embodiment said barrier 192 is mounted on said standard 10 as at 194 and is movable from the extended dotted line position of FIG. 2 in which it intercepts the advancing end end of said tubing T to position it for zeroing of said counter 142 as aforesaid. to the retracted solid line position shown in the same view in which the tubing T is free for further advancement.

Having regard to the foregoing description of the curving apparatus. attention is now directed to the method of forming successive curves in malleable tubing T in relatively offset planes. Essentially, this method, broadly stated. includes the steps of: supporting the tubing T in said rotatable chuck C, with one end of tubing T projecting through said chuck C; training said projecting tubing end between said forming die 2 and wiper die 4; withdrawing said tubing T through said chuck C by its projecting end in linear increments and advancing it between said forming die 2 and wiper die 4; curving pre-selected portions of said tubing T around said forming die 2 to form curves therein, and rotating said chuck C after at least one of the curves to procure a further curve in a plane which is offset relative to the plane of its predecessor.

More particularly, the various steps of the method aforesaid are achieved herein by manipulating the curving apparatus pursuant to curving pattern instructions. That is to say, curving pattern instructions will indicate initial adjustments to the curving apparatus to include adjusting said forming die 2 and said dial 176 correspondingly to a selected tubing size with said barrier 192 being moved to its extended position aforesaid. The selected tubing T is then inserted in said chuck C and advanced therethrough against the bias of said resilient fingers 112 to where it engages and meshes with said advancing element I40. Thereafter, said crank 152 is turned to axially advance said tubing T to starting position i.e., abut said extended starting barrier I92 as shown schematically in FIG. ll in which event said counter 142 is zeroed; said barrier 192 being subsequently moved to its retracted position freeing said tubing T for further advancement.

Ordinarily, the curving pattern instructions for the first curve require that the tubing T be advanced a specific linear distance as measured by said counter I42 to first curving position as illustrated schematically in FIG 12. ln addition thereto, the instructions also require that said fixed stop member 56 be positioned in said locus according to the degree of curvature desired in the first curve.

Thereafter said lever 52 is manipulated by the operator in an understood manner to move said wiper die 4 to wrap the tubing T about said forming die 2 as shown schemaitcally in FIG. 13 until said rotatable stop member 58 is intercepted by said fixed stop member 56 as aforesaid whereupon said wiper die 4 is reversed to its normal position.

Upon completion of the first curve, the tubing T is again advanced pursuant to instructions to the next succeeding curving position as shown schematically in FIG. 14; said fixed stop member 56 being once again adjusted as required.

Should the curving pattern instructions require that this curve be in a plane which is offset relative to the plane of its predecessor, then said chuck C is rotated prior to its formation; the amount of rotation desired of said chuck C being measured by its gauge 134. Afterwards, said tubing T is again wrapped about said forming die 2 as shown schematically in FIG. 15; it being recognized that the plane of the second curve is offset relative to that of the first curve.

Each succeeding curve is also initiated pursuant to curving pattern instructions by repeating the curving procedure aforesaid.

What we claim is:

1. Apparatus for forming successive curves in malleable tubing in relatively offset planes comprising, in combination:

a tube curving head including a forming die about which malleable tubing is curvable and a wiper die spaced from said forming die to permit the tubing to be interposed between it and the forming die, the wiper die being movable to curve said interposed tubing around said forming die whereby to form curves therein;

a rotatable chuck for supporting said tubing in inter- 6S through the chuck towards the forming die. the chuck including means for yieldingly supporting and gripping the tubing to cause the tubing to rotate with the chuck, said gripping means permitting the tubing to be advanced through the chuck while it is gripped for rotation, and

means for engaging said tubing supported in said chuck and for advancing metered portions thereof through the chuck, while the tubing is gripped for rotation therewith, to said tube curving head for curving as aforesaid; said engaging means including an element in tangential engagement with the tubing and rotatable about an axis transverse to the axis of rotation of the chuck,

the tubing being co-rotatable with the chuck to permit formation of successive curves in relatively offset planes.

2. Apparatus as defined in claim 1 wherein:

said chuck includes a gauge for metering its rotation.

3. Apparatus as defined in claim 1 and further including:

a removable starting barrier at which said tubing is initially positionable prior to curving.

4. Apparatus as defined in claim wherein:

said wiper die includes a sheave rotatably engaging said tubing when the wiper die is moved to curve the tubing about the forming die as aforesaid.

5. Apparatus as defined in claim 1 wherein:

said means for engaging said tubing and advancing metered portions thereof includes an element for advancing said tubing in equal linear increments. and a counter for counting said increments,

6. Apparatus as defined in claim 5 wherein:

said element is circular and is mounted for tangential engagement with said tubing on an axis which is inclinable to accommodate tubing of various sizes.

7. Apparatus as defined in claim 1 wherein:

said means for yieldingly supporting and gripping the tubing includes a complement of resilient fingers for resliently gripping the tubing in the chuck and positioning and supporting it in the axis of rotation of the said chuck.

8. Apparatus as defined in claim 7 wherein:

said fingers are resiliently mounted to project in an angular converging relationship towards a common focus on the rotary axis of said chuck; the fingers being biased towards said focus and being resiliently spreadable to permit tubing of various sizes to be gripped and supported between them in the chuck axis aforesaid.

9. Apparatus as defined in claim 7 wherein:

said fingers include rollers engageable with said tubing to facilitate advancement thereof through said chuck as aforesaid. movement.

10. Apparatus as defined in claim 1 wherein:

said wiper die is mounted for movement in an orbit about said forming die; means being provided for procuring such movment.

11. Apparatus as defined in claim 10 and further including:

means for limiting the movement of said wiper die about said forming die to procure curves of specific proportions.

12. Apparatus as defined in claim it wherein:

said limiting means includes cooperating fixed and rotatable stop members, the rotatable stop member being mounted for movement through a finite locus in tandem with said wiper die and said fixed stop member being positionable at various points in that locus to intercept the rotatable stop member to limit movement of said wiper die.

13. Apparatus as defined in claim 12 wherein:

a register is associated with said limiting means for identifying the respective points at which its said fixed stop member is positionable as aforesaid.

14. Apparatus as defined in claim wherein:

said wiper die is mounted to maintain a fixed orbit about said forming die; the forming die being adjustable to permit tubing of various sizes to be installed between it and the wiper die.

l5. Apparatus as defined in claim 14 wherein:

said forming die has confronting jaws defining and bounding a groove on the rim of the forming die in which the tubing is seatable; said jaws being spreadable and contractable to vary the width of the groove in conformity with the tubing sizes. the variance in the width of the groove constituting the forming die adjustment aforesaid.

16. Apparatus as defined in claim l4 wherein:

said forming die includes a spool with collars constituting jaws which are screw-threadedly engaged with the spool for movement thereon towards and away from each other, defining and bounding a groove on the rim of said spool;

means for interconnecting said collars for conjoint rotation about said spool, the screw threading being right and left hand procuring variation in the spacing between the collars when they are rotated as aforesaid. and

means for releasably locking said collars to said spool for preventing such rotation.

17. Apparatus as defined in claim 16 wherein:

said collars are chamfered imparting a V-shaping to said groove.

18. Apparatus as defined in claim 16 wherein:

said interconnecting means includes a scale for indicating variations in the spacing of said collars when they are rotated as aforesaid.

19. Apparatus as defined in claim 17 wherein:

said interconnecting means includes a scale for indicating variations in the spacing of said collars when they are rotated as aforesaid;

means being provided for limiting the movement of said wiper die about said forming die to procure curves of specific proportions, said limiting means including cooperating fixed and rotatable stop members, the rotatable stop member being mounted for movment through a finite locus in tandem with said wiper die and said fixed stop member being positionable at various points in that locus to intercept the rotatable stop member to limit movement of said wiper die, said wiper die including a sheave rotatably engaging said tubing when the wiper die is moved to curve the tubing about the forming die as aforesaid;

a register being associated with said limiting means for identifying the respective points at which its said fixed stop member is positionable as aforesaid;

said chuck includes a complement of resilient fingers having rollers for resiliently gripping the tubing in the chuck and positioning and supporting it in the axis of rotation of the said chuck. said fingers being mounted to project in an angular converging relationship towards a common focus on the rotary axis ofsaid chuck, the fingers being biased towards said focus and being reiliently spreadable to permit tubing of various sizes to be gripped and supported between them in the chuck axis aforesaid; said chuck including a gauge for metering its rotation;

said advancing means includes a circular element for advancing said tubing in equal linear increments, and a counter for counting said increments. said element being mounted for tangential engagement with said tubing on an axis which is inclinable to accommodate tubing of various sizes, and

a removable starting barrier at which said tubing is initially positionable prior to curving. 

1. Apparatus for forming successive curves in malleable tubing in relatively offset planes comprising, in combination: a tube curving head including a forming die about which malleable tubing is curvable and a wiper die spaced from said forming die to permit the tubing to be interposed between it and the forming die, the wiper die being movable to curve said interposed tubing around said forming die whereby to form curves therein; a rotatable chuck for supporting said tubing in interposed relation between said forming die and wiper die as aforesaid, said chuck being of the feed-through type permitting the tubing to be advanced through the chuck towards The forming die, the chuck including means for yieldingly supporting and gripping the tubing to cause the tubing to rotate with the chuck, said gripping means permitting the tubing to be advanced through the chuck while it is gripped for rotation, and means for engaging said tubing supported in said chuck and for advancing metered portions thereof through the chuck, while the tubing is gripped for rotation therewith, to said tube curving head for curving as aforesaid; said engaging means including an element in tangential engagement with the tubing and rotatable about an axis transverse to the axis of rotation of the chuck, the tubing being co-rotatable with the chuck to permit formation of successive curves in relatively offset planes.
 2. Apparatus as defined in claim 1 wherein: said chuck includes a gauge for metering its rotation.
 3. Apparatus as defined in claim 1 and further including: a removable starting barrier at which said tubing is initially positionable prior to curving.
 4. Apparatus as defined in claim 1 wherein: said wiper die includes a sheave rotatably engaging said tubing when the wiper die is moved to curve the tubing about the forming die as aforesaid.
 5. Apparatus as defined in claim 1 wherein: said means for engaging said tubing and advancing metered portions thereof includes an element for advancing said tubing in equal linear increments, and a counter for counting said increments.
 6. Apparatus as defined in claim 5 wherein: said element is circular and is mounted for tangential engagement with said tubing on an axis which is inclinable to accommodate tubing of various sizes.
 7. Apparatus as defined in claim 1 wherein: said means for yieldingly supporting and gripping the tubing includes a complement of resilient fingers for resliently gripping the tubing in the chuck and positioning and supporting it in the axis of rotation of the said chuck.
 8. Apparatus as defined in claim 7 wherein: said fingers are resiliently mounted to project in an angular converging relationship towards a common focus on the rotary axis of said chuck; the fingers being biased towards said focus and being resiliently spreadable to permit tubing of various sizes to be gripped and supported between them in the chuck axis aforesaid.
 9. Apparatus as defined in claim 7 wherein: said fingers include rollers engageable with said tubing to facilitate advancement thereof through said chuck as aforesaid. movement.
 10. Apparatus as defined in claim 1 wherein: said wiper die is mounted for movement in an orbit about said forming die; means being provided for procuring such movment.
 11. Apparatus as defined in claim 10 and further including: means for limiting the movement of said wiper die about said forming die to procure curves of specific proportions.
 12. Apparatus as defined in claim 11 wherein: said limiting means includes cooperating fixed and rotatable stop members, the rotatable stop member being mounted for movement through a finite locus in tandem with said wiper die and said fixed stop member being positionable at various points in that locus to intercept the rotatable stop member to limit movement of said wiper die.
 13. Apparatus as defined in claim 12 wherein: a register is associated with said limiting means for identifying the respective points at which its said fixed stop member is positionable as aforesaid.
 14. Apparatus as defined in claim 10 wherein: said wiper die is mounted to maintain a fixed orbit about said forming die; the forming die being adjustable to permit tubing of various sizes to be installed between it and the wiper die.
 15. Apparatus as defined in claim 14 wherein: said forming die has confronting jaws defining and bounding a groove on the rim of the forming die in which the tubing is seatable; said jaws being spreadable and contractable to vary the width of the groove in conformity with the tubing sizes, the variance in the widtH of the groove constituting the forming die adjustment aforesaid.
 16. Apparatus as defined in claim 14 wherein: said forming die includes a spool with collars constituting jaws which are screw-threadedly engaged with the spool for movement thereon towards and away from each other, defining and bounding a groove on the rim of said spool; means for interconnecting said collars for conjoint rotation about said spool, the screw threading being right and left hand procuring variation in the spacing between the collars when they are rotated as aforesaid, and means for releasably locking said collars to said spool for preventing such rotation.
 17. Apparatus as defined in claim 16 wherein: said collars are chamfered imparting a V-shaping to said groove.
 18. Apparatus as defined in claim 16 wherein: said interconnecting means includes a scale for indicating variations in the spacing of said collars when they are rotated as aforesaid.
 19. Apparatus as defined in claim 17 wherein: said interconnecting means includes a scale for indicating variations in the spacing of said collars when they are rotated as aforesaid; means being provided for limiting the movement of said wiper die about said forming die to procure curves of specific proportions, said limiting means including cooperating fixed and rotatable stop members, the rotatable stop member being mounted for movment through a finite locus in tandem with said wiper die and said fixed stop member being positionable at various points in that locus to intercept the rotatable stop member to limit movement of said wiper die, said wiper die including a sheave rotatably engaging said tubing when the wiper die is moved to curve the tubing about the forming die as aforesaid; a register being associated with said limiting means for identifying the respective points at which its said fixed stop member is positionable as aforesaid; said chuck includes a complement of resilient fingers having rollers for resiliently gripping the tubing in the chuck and positioning and supporting it in the axis of rotation of the said chuck, said fingers being mounted to project in an angular converging relationship towards a common focus on the rotary axis of said chuck, the fingers being biased towards said focus and being reiliently spreadable to permit tubing of various sizes to be gripped and supported between them in the chuck axis aforesaid; said chuck including a gauge for metering its rotation; said advancing means includes a circular element for advancing said tubing in equal linear increments, and a counter for counting said increments, said element being mounted for tangential engagement with said tubing on an axis which is inclinable to accommodate tubing of various sizes, and a removable starting barrier at which said tubing is initially positionable prior to curving. 